Localized juvenile spongiotic gingival hyperplasia possibly originates from the junctional gingival epithelium—an immunohistochemical study

Aims To immunohistochemically evaluate the cytokeratin ( CK ) pattern of expression in localized juvenile spongiotic gingival hyperplasia ( LJSGH ) as compared with the gingival epithelium ( GE ). Methods and results Ten cases of LJSGH were semiquantitatively evaluated for the immunohistochemical pattern of CK 1/10, CK 4, CK 8/18, and CK 19. GE controls were taken from 10 cases of reactive gingival fibroepithelial hyperplasia. GE s showed mean positivity rates of 80% for both CK 1/10 and CK 4, and 5% for both CK 8/18 and CK 19. LJSGH s showed mean positivity rates of 65% for CK 19, 60% for CK 8/18, 30% for CK 4, and 5% for CK 1/10. The differences between LJSGH s and GE s were statistically significant ( P  < 0.01). Conclusions The LJSGH pattern of CK expression is reminiscent of the profile described in the literature for the junctional epithelium ( JE ). Possibly, JE exteriorized from the gingival sulcus would be more prone to irritation from a variety of sources, resulting in inflammation and hyperplasia, with the subsequent development of LJSGH .